Embodiments of the present invention relate to a surface-mount solder method and apparatus for improved decoupling capacitance.
Power delivery is a significant concern in the design and operation of a microelectronic device. Where the microelectronic device is a processor or an application-specific integrated circuit (ASIC), an adequate current delivery, a steady voltage, and an acceptable processor transient response are desirable characteristics of the overall microelectronic device package. One of the methods for responding to a processor transient is to place a high-performance capacitor as close to the processor as possible to shorten the transient response time. Although a large-capacity and high-performance capacitor is preferable to answer the processor transients, the capacitor is in competition for space in the immediate vicinity of the processor. This may involve making a cutout in a portion of a board or socket to make room for the capacitor. A cutout in a board is a factor for increasing overall package size, which is counter to the trend to miniaturize. A cutout is also a factor for increasing the loop inductance path for a package, which can have a negative impact on the performance of the microelectronic device.
The loop inductance path is often a convoluted path that complicates the impedance of the package. FIG. 11 is a depiction of an existing system 10 including a substrate 12 and a top structure 24 that includes an electronic component 26. A decoupling capacitor 30 is mounted upon the substrate 12. A convoluted current path 64 can be traced between the capacitor 30, the electronic component 26, and back to the capacitor 30. A convoluted path 64 or convoluted inductance loop is defined as a current that flows in a first pre-component direction 66 and in a substantially reverse, second pre-component direction 68. xe2x80x9cPre-componentxe2x80x9d means that the current in this section of the current-convoluted current loop path 64 has not passed, either in whole or in part, through the component 26, but it has reversed its flow direction. A convoluted path is also defined as a current that flows in a first post-component direction 70 and a substantially reverse, second post-component direction 72. xe2x80x9cPost-componentxe2x80x9d means that the current in this section of the convoluted current loop path 64 has not passed, either in whole or in party, through the component 26 but it likewise has reversed its flow direction. Such reversal of flow direction creates complicated inductance that is detrimental to performance.